1. Field of the Invention
The present invention relates to a water meter service coupling and, more specifically, to a water meter service coupling which connects a water service line to a water meter and which has an expandable piston slidably disposed within a housing so as to facilitate removal and/or replacement of the water meter by allowing for expansion of the water service line upon disconnection of the water meter.
2. Description of Related Art
There are several methods for installing water meters. One conventional method for installing a meter is to place the meter below ground where it is protected by a meter box. This method allows for access to the meter for reading and properly charging a water customer the correct amount of money for the amount of water used over a given period of time. The meter is connected to a water main by means of water service lines. The service lines vary in materials from copper tubing, polyethylene tubing, galvanized steel, to polyvinyl chloride. The lengths of the service lines from the main to the meter and from the meter to the home may also vary.
Inside the meter box is a "cut off" valve which is connected to the service line. This valve is connected to the water meter by the first of two "union joint" nipples used in the meter box. The first nipple is screwed into the valve and the "union joint" is then conventionally connected to the inlet side of the water meter. A second "union joint" nipple is usually employed on the outlet side of the water meter leading to the house. The second "union joint" nipple generally serves two purposes. First, it allows the utility company to remove the water meter for repair or replacement. Second, it allows the plumber to connect to the meter for the purposes of running the water line from the meter to the house. Examples of conventional water meter nipples are disclosed in U.S. Pat. No. 2,576,630 to Mueller et al and U.S. Pat. No. 1,997,845 to Adams.
This conventional construction suffers from several problems however. The service line from the water main to the meter and from the meter to the home almost always expands over time before an attempt is made to remove the water meter. Expansion tension is caused by the service line being laid in the service ditch in a manner contrary to being installed in a flat or straight position in the bottom of the ditch. Next, all pipe fittings are connected from the water main to the house, including the water meter. The ditch is then filled with dirt or other suitable material. The weight of the dirt causes the service line to lay flat in the bottom of the ditch. The service line, being forced to lay flat because of the weight of the dirt, extends to cover a longer distance than when being left uncovered by dirt. This attempt, to extend to cover a longer distance, is a cause of the service line extension or expansion when the water meter is removed for replacement or repair. Expansion and contraction of the same service line is also caused by seasonal temperature variations. This in turn causes a ground temperature change that is then transmitted to the service lines causing the expansion or contraction. This makes it very difficult to remove or install a replacement water meter.
Accordingly, a need in the art exists for a simple and economical means for coupling a water meter to a service line which allows for expansion of the service line so as to provide for easier removal and/or replacement of the water meter.